The present invention relates to a method for generating antenna follow-up signals to track another antenna which transmits a beacon signal, wherein a sum signal and at least one difference signal are derived in a mode coupler from the beacon signal received by the movable antenna. The difference signal is subjected to cyclical changes in phase and, while traversing the different phase states, is superposed on the sum signal to form an amplitude modulated signal. Finally a determination is made as to whether the amplitude modulated signal produced by the superposition of the difference signal and the sum signal undergoes a positive or negative change in amplitude when the difference signal goes from one phase state to another and the amount by which the amplitude modulated signal changes. Such a method for producing antenna follow-up signals is disclosed in European patent application EP No. 0,093,234.A1.
In satellite transmission systems it is desirable to provide follow-up devices which are as simple and compact as possible. This is particularly important for the antennas of satellites and also for the antennas of small ground stations which are installed close to users.